1. Field of the Invention
The present invention relates to a sheet-feed device for using sheet-feed rollers to feed one sheet at a time from a stack of sheets in a hopper.
2. Description of the Related Art
Japanese Laid-Open Patent Application No. HEI-7-81786 and U.S. Pat. No. 5,026,042 describe a sheet-supply device used in a printer. The sheet-supply device includes a sheet-feed roller and a collar disposed on the same rotational shaft. The sheet-feed roller appears is substantially circular when viewed from the side, except for an arch-shaped cut-out portion removed from its periphery. The collar is disk shaped and has a radius smaller than that of greatest radius of the sheet-feed roller, but greater that the radius at the arch-shaped cut-out portion. Therefore, when the rotation of the sheet-feed roller brings the arch-shaped cut-out portion into confrontation with a sheet, the collar comes into contact with the sheet so that the sheet is prevented from rising up. By preventing the sheet from rising up, problems that often occur when feeding sheets from a stack in the hopper, such as skipping sheets or redundant sheet supply, that is, supplying two or more sheets stacked together, can be prevented.